A whopping number of Californians might be part of a political party by mistake

Reuters A surprisingly large group of California voters could be out of luck when it comes time to vote in June's increasingly consequential primaries because they registered for the wrong political party inadvertently.

The AIP boasts nearly half a million registered members, according to the paper, making it the state's largest third party.

The American Independent Party traces its roots back to the late 1960s, when segregationist former Alabama Gov. George Wallace ran on the party's ticket for president in 1968. The party's chairman said that it's "not segregationist" anymore. Instead, he told the Times that it's a "conservative, constitutionalist party."

Democrats will allow independent voters — those who are registered as having "no party preference" — to cast ballots in the June primary. Republicans will hold a closed primary, meaning that only registered GOP voters can participate. AIP-registered voters can cast ballots only for candidates on the party's ballot. The deadline to change registration is May 23, according to the Times.

Hollywood stars Emma Stone and Demi Moore, as well as Patrick Schwarzenegger, son of movie star and former Republican California Gov. Arnold Schwarzenegger, were mistakenly registered with the AIP.

The party accounts for about 3% of the 17.2 million registered California voters.

Former Secretary of State Hillary Clinton leads Bernie Sanders, a Vermont senator, by 10 points in California, according to the RealClearPolitics average of several recent polls. More than 450 delegates are at stake for Democrats, the largest total of any of the 50 states. Sanders has traditionally fared better in states with open primaries.

Republicans, too, have their biggest treasure trove of delegates in play in the Golden State, with 172 up for grabs. GOP frontrunner Donald Trump leads Ted Cruz, a Texas senator, by nine points, according to the RealClearPolitics average.